A new firmware by AT&T has been leaked, intended for the AT&T Galaxy S3 I747 smartphone. The firmware update; UCUEMJ2 Android 4.3 Jelly Bean, brought with it, new bug fixes and speed upgrades alongside Android 4.3 goodies. While the update can be installed via OTA, if for some reason you failed to receive the update, you can install it by following our guide.

Please do note, that one of the ROM file(s) linked in this post is pre-rooted, has KNOX removed and SELinux disabled (Permissive) and the other is not rooted, has KNOX enabled and SELinux enabled (Enforcing). Should you choose to upgrade using the version with KNOX enabled, you will find out that it has a secured bootloader, which will subsequently make it very difficult for you to install other ROMs.

Disclaimer:This guide includes instructions to flash the official firmware on your AT&T Galaxy S3 I747. During the process, you might lose all your existing installed apps and personal settings. It is therefore necessary for you to follow the guide carefully. Also, please, do mind that this tutorial is only for AT&T Galaxy S3 I747. Don’t try this guide in any other Android device.

Put the AT&T Galaxy S3 I747 in Recovery Mode by pressing and holding Volume Up, Power and Home buttons until Samsung Galaxy logo appears in phone screen. Wait for a few seconds and you will be in ‘recovery mode’.

Factory reset your phone.

Flash the Bootloader/Modem file first.

In CWM: Click on ‘install zip from sdcard’, then opt for ‘choose zip from sdcard’ option, from here look for the copied ‘d2att_I747UCUEMJ2_bootloader_modem.zip’ file, click on it to install.

In TWRP: Click on install, and look for the copied ‘d2att_I747UCUEMJ2_bootloader_modem.zip’ file. Click on it to install.

Once the bootloader files have been installed, you can choose to install either the rooted version of UCEUMJ2 Android 4.3 Jelly Bean firmware for your AT&T Galaxy S3, or the non-rooted version.

Non-Rooted Version:

In CWM: Click on ‘install zip from sdcard’, then opt for ‘choose zip from sdcard’. Look for the ‘d2att_I747UCUEMJ2_stock_noroot.zip’. Confirm the install process.

In TWRP: Click install, look for ‘d2att_I747UCUEMJ2_stock_noroot.zip’, click to install.

Rooted Version:

In CWM: Click on ‘install zip from sdcard’, then opt for ‘choose zip from sdcard’. Look for the ‘d2att_I747UCUEMJ2_root_noknox.zip’. Confirm the install process.

In TWRP: Click install, look for ‘d2att_I747UCUEMJ2_root_noknox.zip’, click to install.

Go back to first screen of ‘Recovery Mode’ and reboot your phone.

If you have followed every point described in the guide, your AT&T Galaxy S3 I747 should now be running Android 4.3 Jelly Bean build I747UCUEMJ2. If there are any issues, feel free to post in the comments section for our staff to take a look at it.

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An audiophile, geek and a cinema fanatic interested in all things technology.